a friend who is a cleric was given a wooden cup a number of years ago by a grateful congregant in south america.  it is approximately 4 inches wide, 4 inches tall and cylindrical.  it appears to me, a novice, that it was turned from a single piece of dark wood like mahogany.  the cup is used to hold altar wine for services.  it has developed several small vertical cracks.  my friend thinks they developed because he dropped it but agrees that it may be wood movement.  in any event, the wine weeps from the cracks and he now cannot use it for services.  can anyone recommend a sealant or other solution which would enable the cup to be restored to use?  i know altar wine has some alcohol content but i do not think it is high.  thanks.  richard champion